Hydrocarbon hydrogenation catalyst composition, a process of treating such catalyst composition, and a process of using such catalyst composition

ABSTRACT

A process of treating a catalyst composition containing palladium, an inorganic support, and a catalyst component, such as silver and/or a modifier such as alkali metal fluoride, is provided. The process involves contacting a catalyst composition with a first treating agent comprising carbon monoxide under a first treating condition to provide a treated catalyst composition. As an option, such treated catalyst composition can then be contacted with a second treating agent comprising a hydrogen-containing fluid under a second treating condition. The treated catalyst composition can be used in a selective hydrogenation process in which highly unsaturated hydrocarbons such as diolefins and/or alkynes are contacted with such treated catalyst composition in the presence of hydrogen to produce less unsaturated hydrocarbons such as monoolefins.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a hydrocarbon hydrogenation catalystcomposition, a process of treating a hydrogenation catalyst composition,and to a hydrogenation process employing such hydrogenation catalystcomposition.

[0002] It is known to one skilled in the art that a less unsaturatedhydrocarbon compound can be produced by a thermal cracking process. Forexample, a fluid stream containing a saturated hydrocarbon such as, forexample, ethane, propane, butane, pentane, naphtha, and the like andcombinations thereof can be fed into a thermal (or pyrolytic) crackingfurnace. Within the furnace, the saturated hydrocarbon is converted toan unsaturated hydrocarbon compound such as, for example, ethylene orpropylene. Such unsaturated hydrocarbons are an important class ofchemicals that find a variety of industrial uses. For example, ethylenecan be used as a monomer or comonomer for producing a polyolefin. Otheruses of unsaturated hydrocarbons are well known to one skilled in theart.

[0003] However, unsaturated hydrocarbons produced by a thermal crackingprocess generally contain an appreciable amount of less desirable highlyunsaturated hydrocarbon(s) such as alkyne(s) or diolefin(s). Forexample, ethylene produced by thermal cracking of ethane is generallycontaminated with a highly unsaturated hydrocarbon, such as acetylene,which must be selectively hydrogenated to a less unsaturatedhydrocarbon, such as ethylene, but not to a saturated hydrocarbon suchas ethane, in a hydrogenation process.

[0004] In addition, catalyst compositions comprising palladium and aninorganic support, such as alumina, are known catalyst compositions forthe hydrogenation of highly unsaturated hydrocarbons such as alkynesand/or diolefins. For example, U.S. Pat. No. 4,484,015 discloses the useof a palladium and silver catalyst composition supported on alumina forthe selective hydrogenation of acetylene to ethylene. Also for example,U.S. Pat. No. 5,510,550 discloses the use of a palladium, silver, andalkali metal catalyst composition supported on alumina for an even moreselective hydrogenation of acetylene to ethylene. The operatingtemperature for the hydrogenation process is selected such thatessentially all highly unsaturated hydrocarbon such as alkyne (e.g.,acetylene) is hydrogenated to its corresponding less unsaturatedhydrocarbon such as alkene (e.g., ethylene) thereby removing the alkynefrom the product stream while only an insignificant amount of alkene ishydrogenated to a saturated hydrocarbon such as alkane (e.g., ethane).Such selective hydrogenation process minimizes the loss of desired lessunsaturated hydrocarbons.

[0005] Thus, the development of a catalyst composition, a process oftreating such catalyst composition, and a process of using such catalystcomposition for the hydrogenation of highly unsaturated hydrocarbonssuch as diolefins (alkadienes) or alkynes to less unsaturatedhydrocarbons such as monoolefins (alkenes) where such catalystcomposition has improved selectivity, increased activity, and/or longeroperating life would be a significant contribution to the art and to theeconomy.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide an improvedprocess of treating a hydrogenation catalyst composition, such as apalladium-containing hydrogenation catalyst composition, and a catalystcomposition prepared according to such treatment process.

[0007] Another object of the present invention is to utilize a catalystcomposition treated by a process of the present invention to hydrogenatea highly unsaturated hydrocarbon, such as acetylene, in admixture with aless unsaturated hydrocarbon, such as ethylene, to produce a furtheramount of less unsaturated hydrocarbon, such as ethylene, without theconcurrent consumption of a significant portion of such less unsaturatedhydrocarbon.

[0008] According to an embodiment of the present invention, a catalystcomposition is provided which can be used for selectively hydrogenatinga highly unsaturated hydrocarbon such as, for example, an alkyne or adiolefin. Such catalyst composition can be prepared by a process whichcomprises treating a hydrogenation catalyst composition, such as apalladium-containing hydrogenation catalyst composition, by contactingsuch catalyst composition with a first treating agent to provide atreated catalyst composition followed by optionally contacting with asecond treating agent. Generally, such first treating agent comprisescarbon monoxide. Generally, such second treating agent comprises ahydrogen-containing fluid.

[0009] According to another embodiment of the present invention, aprocess which can be used for selectively hydrogenating a highlyunsaturated hydrocarbon to a less unsaturated hydrocarbon is provided.The process comprises contacting a highly unsaturated hydrocarbon withhydrogen, in the presence of a catalyst composition which has beentreated according to a process of the present invention, under acondition sufficient to effect a selective hydrogenation of the highlyunsaturated hydrocarbon.

[0010] Other objects and advantages of the present invention will beapparent from the detailed description of the present invention and theappended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0011] As used in the present invention, the term “fluid” denotes gas,liquid, vapor, or combinations thereof. The term “palladium” refers topalladium metal. The term “silver” refers to silver metal. The term“substantial” or “substantially” generally means more than trivial. Theterm “saturated hydrocarbon” refers to any hydrocarbon which does notcontain any carbon-to-carbon double bonds or carbon-to-carbon triplebonds. Examples of saturated hydrocarbons include, but are not limitedto, ethane, propane, butanes, pentanes, hexanes, octanes, decanes,naphtha, and the like and combinations thereof.

[0012] The term “highly unsaturated hydrocarbon” refers to a hydrocarbonhaving a triple bond or two or more double bonds between carbon atoms inthe molecule. Examples of highly unsaturated hydrocarbons include, butare not limited to, aromatic compounds such as benzene and naphthalene;alkynes such as acetylene, propyne (also referred to asmethylacetylene), and butynes; diolefins such as propadiene, butadienes,pentadienes (including isoprene), hexadienes, octadienes, anddecadienes; and the like and combinations thereof.

[0013] The term “less unsaturated hydrocarbon” refers to a hydrocarbonin which a triple bond in a highly unsaturated hydrocarbon ishydrogenated to a double bond or a hydrocarbon in which the number ofdouble bonds is one less, or at least one less, than that in the highlyunsaturated hydrocarbon. Examples of less unsaturated hydrocarbonsinclude, but are not limited to, monoolefins such as ethylene,propylene, butenes, pentenes, hexenes, octenes, decenes, and the likeand combinations thereof.

[0014] The term “hydrogenation process” refers to a process whichconverts a highly unsaturated hydrocarbon such as an alkyne or adiolefin to a less unsaturated hydrocarbon such as a monoolefin or asaturated hydrocarbon such as an alkane. The term “selective” refers tosuch hydrogenation process in which a highly unsaturated hydrocarbonsuch as an alkyne or a diolefin is converted to a less unsaturatedhydrocarbon such as a monoolefin without further hydrogenating the lessunsaturated hydrocarbon to a saturated hydrocarbon such as an alkane.Thus, for example, when a highly unsaturated hydrocarbon is converted toa less unsaturated hydrocarbon without further hydrogenating such lessunsaturated hydrocarbon to a saturated hydrocarbon, the hydrogenationprocess is “more selective” than when such highly unsaturatedhydrocarbon is hydrogenated to a less unsaturated hydrocarbon and thenfurther hydrogenated to a saturated hydrocarbon.

[0015] The term “gas hourly space velocity” refers to the numericalratio of the rate at which a treating agent, such as a first or secondtreating agent of the present invention, is charged to a treating zoneof the present invention (or the numerical ratio of the rate at which ahydrocarbon-containing fluid of the present invention is charged to ahydrogenation zone of the present invention) in liters per hour atstandard condition of temperature and pressure (“STP”) divided by theliters of catalyst composition contained in the treating zone to whichthe treating agent is charged (or the liters of treated catalystcomposition contained in the hydrogenation zone to which thehydrocarbon-containing fluid is charged).

[0016] The term “treated catalyst composition” refers to a catalystcomposition which has been subjected to a treating process of thepresent invention.

[0017] According to an embodiment of the present invention, a catalystcomposition which can be used to selectively hydrogenate a highlyunsaturated hydrocarbon (such as an alkyne or a diolefin) to a lessunsaturated hydrocarbon (such as an alkene or a monoolefin) is provided.The catalyst composition comprises (a) palladium such as palladiummetal, palladium oxide, or combinations thereof, (b) a catalystcomponent selected from the group consisting of silver, modifiers, andthe like and combinations thereof, and (c) an inorganic support. Thepalladium can be present as “skin” on or near the surface of thecatalyst composition and the catalyst component can be distributed asskin with the palladium or throughout the catalyst composition. Anexample of a suitable modifier includes, but is not limited to, analkali metal compound. The catalyst composition to be treated accordingto a process of the present invention can be any suitable commerciallyavailable catalyst composition which, after being subjected to atreating process of the present invention, can be used to selectivelyhydrogenate a highly unsaturated hydrocarbon (such as an alkyne or adiolefin) to a less unsaturated hydrocarbon (such as an alkene or amonoolefin) according to a process of the present invention. Thecatalyst composition subjected to a treating process of the presentinvention can be a new catalyst composition or a regenerated catalystcomposition. A treated catalyst composition of the present invention hasan improved selectivity, an increased activity, and/or a longeroperating life than a catalyst composition which has not been treatedaccording to a treating process of the present invention.

[0018] A suitable commercially available catalyst composition which canbe treated according to a process of the present invention can be madeby any manner or method(s) known in the art. For example, the palladiumand catalyst component(s) may be incorporated into, onto, or with theinorganic support by any suitable means or method(s) for incorporatingthe palladium and catalyst component(s) into, onto, or with a substratematerial, such as an inorganic support, which results in the formationof a palladium and catalyst component-incorporated inorganic supportwhich can then be dried and calcined to thereby provide a catalystcomposition which can then be subjected to a treatment process of thepresent invention. Examples of means or method(s) for incorporatinginclude, but are not limited to, impregnating, soaking, spraying, andthe like and combinations thereof. A preferred method of incorporatingis soaking.

[0019] The term “skin” refers to the exterior surface of the catalystcomposition which can contain components, such as palladium, of thecatalyst composition. The skin can be any thickness as long as suchthickness can promote the hydrogenation process(es) disclosed herein.Generally, the thickness of the skin is at least about 5 microns.Generally, the thickness of the skin is no more than about 1000 microns,preferably no more than about 750 microns. Preferably, the palladium isconcentrated in the skin of the catalyst composition whereas thecatalyst component is distributed throughout the catalyst composition.Various skin catalyst compositions have been developed. See for exampleU.S. Pat. No. 4,404,124 and U.S. Pat. No. 4,484,015, the disclosures ofwhich are incorporated herein by reference.

[0020] Generally, palladium can be present in the catalyst compositionin any weight percent so long as the palladium is substantiallyconcentrated as skin on or near the surface of the catalyst compositionand that the resulting catalyst composition is effective in selectivelyhydrogenating a highly unsaturated hydrocarbon (such as an alkyne) to aless unsaturated hydrocarbon (such as an alkene). Generally, thecatalyst composition comprises at least about 0.0001 weight percentpalladium based on the total weight of the composition, preferably atleast about 0.0005 weight percent palladium, and more preferably atleast about 0.001 weight percent palladium. Generally, the catalystcomposition comprises no more than about 3 weight percent palladiumbased on the total weight of the composition, preferably no more thanabout 1.5 weight percent palladium, and more preferably no more thanabout 1.0 weight percent palladium.

[0021] Examples of suitable palladium compounds which can be used forincorporating the palladium of such palladium compounds into, onto, orwith an inorganic support include, but are not limited to, palladiumbromide, palladium chloride, palladium iodide, palladium nitrate,palladium nitrate hydrate, tetraamine palladium nitrate, palladiumoxide, palladium oxide hydrate, palladium sulfate, and the like andcombinations thereof. The palladium can have any available oxidationstate. The presently preferred palladium compound is H₂PdCl₄. When addedto the support by impregnation from solution, some of the compounds canbe added from aqueous solution, but others will require non-aqueoussolvents such as alcohols, hydrocarbons, ethers, ketones and the like.

[0022] When the catalyst composition comprises a catalyst componentcomprising silver, the silver can be present in the catalyst compositionin any weight percent as long as the resulting catalyst composition iseffective in selectively hydrogenating a highly unsaturated hydrocarbon(such as an alkyne) to a less unsaturated hydrocarbon (such as analkene). Generally, the catalyst composition comprises at least about0.0003 weight percent silver based on the total weight of thecomposition, preferably at least about 0.003 weight percent silver basedon the total weight of the catalyst composition, and more preferably atleast about 0.005 weight percent silver. Generally, the catalystcomposition comprises no more than about 20 weight percent silver basedon the total weight of the composition, preferably no more than about 10weight percent silver, and more preferably no more than about 5 weightpercent silver.

[0023] Suitable examples of silver compounds for use in incorporating,preferably impregnating, the silver of such silver compound(s) into,onto, or with an inorganic support include, but are not limited to,silver nitrate, silver acetate, silver cyanide and the like andcombinations thereof. The presently preferred silver compound is silvernitrate.

[0024] In lieu of a catalyst component comprising silver or in additionto a catalyst component comprising silver, the catalyst composition cancomprise a catalyst component comprising a modifier, preferably analkali metal compound. Any alkali metal compound(s) can be used inpreparing a catalyst composition of the present invention as long as theresulting catalyst composition is effective in selectively hydrogenatinga highly unsaturated hydrocarbon (such as an alkyne) to a lessunsaturated hydrocarbon (such as an alkene). Suitable examples of alkalimetal compounds for use in incorporating, preferably impregnating, thealkali metal compound(s) into, onto, or with the inorganic supportgenerally include, but are not limited to, alkali metal halides, alkalimetal hydroxides, alkali metal carbonates, alkali metal bicarbonates,alkali metal nitrates, alkali metal carboxylates, and the like andcombinations thereof. Preferably, the alkali metal compound is an alkalimetal halide, more preferably the alkali metal compound is an alkalimetal iodide or an alkali metal fluoride. Generally, the alkali metal ofsuch alkali metal compound is selected from the group consisting ofpotassium, rubidium, cesium, and the like and combinations thereof.Preferably, the alkali metal of such alkali metal compound is potassium.Preferably, the alkali metal compound is potassium iodide (KI) and, morepreferably, the alkali metal compound is potassium fluoride (KF).

[0025] Further examples of suitable alkali metal compounds include, butare not limited, sodium fluoride, lithium fluoride, rubidium fluoride,cesium fluoride, sodium iodide, lithium iodide, rubidium iodide, cesiumiodide, sodium chloride, potassium chloride, lithium chloride, rubidiumchloride, cesium chloride, sodium bromide, potassium bromide, lithiumbromide, rubidium bromide, cesium bromide, sodium hydroxide, potassiumhydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide,sodium oxide, potassium oxide, lithium oxide, rubidium oxide, cesiumoxide, sodium carbonate, potassium carbonate, lithium carbonate,rubidium carbonate, cesium carbonate, sodium nitrate, potassium nitrate,lithium nitrate, rubidium nitrate, cesium nitrate, and the like andcombinations thereof.

[0026] Generally, the catalyst composition comprises a modifier,preferably an alkali metal. Generally, the catalyst compositioncomprises at least about 0.001 weight percent alkali metal based on thetotal weight of the catalyst composition, preferably at least about0.005 weight percent alkali metal, and more preferably at least about0.01 weight percent alkali metal. Generally, the catalyst compositioncomprises no more than about 10 weight percent alkali metal based on thetotal weight of the composition, preferably no more than about 5 weightpercent alkali metal, and more preferably no more than about 2 weightpercent alkali metal. Generally, the weight ratio of alkali metal topalladium is at least about 0.05:1, preferably at least about 0.1:1, andmore preferably at least about 0.2:1. Generally, the weight ratio ofalkali metal to palladium is no more than about 500:1, preferably nomore than about 200:1, and more preferably no more than about 100:1.

[0027] When the catalyst composition comprises an alkali metal compoundcomprising an alkali metal iodide, the catalyst composition generallycomprises at least about 0.03 weight percent iodine (chemically bound asiodide) (on a total catalyst composition weight basis), preferably atleast about 0.1 weight percent iodine, and more preferably at leastabout 0.2 weight percent iodine. Generally, the catalyst compositioncomprises no more than about 10 weight percent iodine, preferably nomore than about 5 weight percent iodine, and more preferably no morethan about 1 weight percent iodine. Generally, the atomic ratio ofiodine to alkali metal is at least about 0.5:1, and preferably at leastabout 1:1. Generally, the atomic ratio of iodine to alkali metal is nomore than about 4:1, and preferably no more than about 3:1. When thealkali metal compound is an alkali metal iodide, it should be used inlieu of silver.

[0028] When the catalyst composition comprises an alkali metal compoundcomprising an alkali metal fluoride, the catalyst composition generallycomprises at least about 0.02 weight percent fluorine (chemically boundas fluoride) (on a total catalyst composition weight basis), preferablyat least about 0.1 weight percent fluorine, and more preferably at leastabout 0.2 weight percent fluorine. Generally, the catalyst compositioncomprises no more than about 10 weight percent fluorine, preferably nomore than about 5 weight percent fluorine, and more preferably no morethan about 1 weight percent fluorine. Generally, the atomic ratio offluorine to alkali metal is at least about 0.5:1, and preferably atleast about 1:1. Generally, the atomic ratio of fluorine to alkali metalis no more than about 4:1, and preferably no more than about 3:1.

[0029] The inorganic support can be any inorganic solid support materialsuitable for use in a hydrogenation catalyst composition of the presentinvention. Preferably, the inorganic support is selected from the groupconsisting of alumina, aluminates, titania, zirconia, and the like andcombinations thereof. The presently more preferred support material isalumina, most preferably alpha-alumina.

[0030] The catalyst composition can have any suitable shape or form aslong as such shape or form is effective in selectively hydrogenating ahighly unsaturated hydrocarbon (such as an alkyne) to a less unsaturatedhydrocarbon (such as an alkene) according to a process of the presentinvention. Suitable examples of forms which a catalyst composition ofthe present invention can be in include, but are not limited to,tablets, pellets, extrudates, spheres, and the like and combinationsthereof. A catalyst composition of the present invention generally has aparticle size of at least about 0.5 millimeters (mm), and preferably atleast about 1 mm. Generally, a catalyst composition has a particle sizeof no more than about 10 mm, preferably no more than about 8 mm, andmore preferably no more than about 6 mm.

[0031] According to an embodiment of the present invention, ahydrogenation catalyst composition, preferably a palladium-containinghydrogenation catalyst composition, is subjected to a treating processof the present invention to obtain a treated catalyst composition of thepresent invention, preferably a treated palladium-containinghydrogenation catalyst composition. Such treated catalyst compositioncan then be utilized in a process of the present invention forselectively hydrogenating a highly unsaturated hydrocarbon (such as analkyne) to a less unsaturated hydrocarbon (such as an alkene) where suchtreated catalyst composition has an improved selectivity, an increasedactivity, and/or a longer operating life than a catalyst compositionwhich has not been treated according to a treating process of thepresent invention.

[0032] A treating process of the present invention comprises contactinga catalyst composition, preferably a palladium-containing catalystcomposition, with a first treating agent comprising carbon monoxideunder a first treating condition effective to provide a treated catalystcomposition.

[0033] The first treating agent comprises carbon monoxide. In additionto carbon monoxide, the first treating agent can further comprise anadditional component. Examples of such additional component of a firsttreating agent of the present invention include, but are not limited to,a hydrogen-containing fluid such as hydrogen gas, an inert gas, ahydrocarbon-containing gas, and the like and combinations thereof.Examples of a suitable inert gas include, but are not limited to,nitrogen, argon, and the like and combinations thereof. Examples of asuitable hydrocarbon-containing gas include, but are not limited to,methane and the like and combinations thereof. Thehydrocarbon-containing gas can be obtained from any suitable, availablesource such as the tail gas from a refinery.

[0034] An example first treating agent of the present inventioncomprises carbon monoxide in the form of formic acid vapor diluted in aninert gas, preferably nitrogen. A preferred first treating agent of thepresent invention comprises carbon monoxide as a dilute stream with aninert gas, preferably nitrogen, as the diluent. Another preferred firsttreating agent of the present invention is a hydrogen-containing fluidwhich contains carbon monoxide. Preferably, such hydrogen-containingfluid is hydrogen gas.

[0035] A first treating agent of the present invention comprises a molepercentage of carbon monoxide (CO) of generally at least about 0.0005,preferably at least about 0.005, and more preferably at least about0.01. A first treating agent of the present invention comprises a molepercentage of CO of generally no more than about 50, preferably no morethan about 25, and more preferably no more than about 10.

[0036] Treating a catalyst composition with a first treating agentaccording to a process of the present invention is generally carried outby contacting such catalyst composition with a first treating agentunder a first treating condition as disclosed herein. The catalystcomposition, which can be contained within a treating zone, can becontacted by any suitable manner with a first treating agent under afirst treating condition as described herein. Such treating zone cancomprise, for example, a reactor vessel.

[0037] A first treating condition of the present invention comprises atemperature of at least about 50° F., preferably at least about 100° F.,and more preferably at least about 200° F. Generally, the first treatingcondition comprises a temperature of no more than about 800° F.,preferably no more than about 600° F., and more preferably no more thanabout 500° F. The first treating condition also comprises a pressure ofat least about atmospheric (i.e., about 14.7 pounds per square inchabsolute) and generally no more than about 150 pounds per square inchabsolute (psia), preferably no more than about 100 (psia). The pressureis more preferably about atmospheric. The first treating condition alsocomprises a time period generally of at least about 0.1 hour andgenerally no more than about 50 hours, preferably no more than about 40hours, and more preferably no more than about 30 hours.

[0038] A first treating condition of the present invention furthercomprises the flow rate at which the first treating agent comprisingcarbon monoxide is charged (i.e., the charge rate of first treatingagent) to the treating zone. The flow rate is such as to provide a gashourly space velocity (“GHSV”) generally exceeding 1 liter of firsttreating agent per liter of catalyst composition per hour(liter/liter/hour). The term “gas hourly space velocity” has beendescribed herein. Generally, the gas hourly space velocity of the firsttreating agent will be at least about 1 liter/liter/hour, preferably atleast about 500 liter/liter/hour, and more preferably at least about 750liter/liter/hour. Generally, the gas hourly space velocity of the firsttreating agent will be no more than about 50,000 liter/liter/hour,preferably no more than about 40,000 liter/liter/hour, and morepreferably no more than about 30,000 liter/liter/hour.

[0039] Treating a catalyst composition with a first treating agent undera first treating condition according to a process of the presentinvention can be operated as a batch process or, preferably, as acontinuous process. In the latter operation, a solid or fixed catalystbed or a moving catalyst bed or a fluidized catalyst bed can beemployed. Preferably, a fixed catalyst bed is employed. Any of theseoperational modes have advantages and disadvantages, and those skilledin the art can select the one most suitable for a particular catalystcomposition and first treating agent.

[0040] Optionally, after contacting a catalyst composition with a firsttreating agent under a first treating condition as disclosed herein, thethus-treated catalyst composition can be further contacted with a secondtreating agent under a second treating condition as disclosed herein.

[0041] The second treating agent comprises a hydrogen-containing fluid.In addition to a hydrogen-containing fluid, the second treating agentcan further comprise an additional component. Examples of suchadditional component of a second treating agent of the present inventioninclude, but are not limited to, carbon monoxide, an inert gas, ahydrocarbon-containing gas, and the like and combinations thereof.Examples of a suitable inert gas include, but are not limited to,nitrogen, argon, and the like and combinations thereof. Examples of asuitable hydrocarbon-containing gas include, but are not limited to,methane and the like and combinations thereof. Thehydrocarbon-containing gas can be obtained from any suitable, availablesource such as the tail gas from a refinery.

[0042] A second treating agent of the present invention is preferably ahydrogen-containing fluid. More preferably, a second treating agent ofthe present invention is hydrogen gas. Most preferably, a secondtreating agent of the present invention is hydrogen gas having a purityof greater than about 98%.

[0043] A second treating agent of the present invention comprises a molepercentage of carbon monoxide (CO) of generally at least about 0.0005,preferably at least about 0.005, and more preferably at least about0.01. A second treating agent of the present invention comprises a molepercentage of CO of generally no more than about 50, preferably no morethan about 25, and more preferably no more than about 10.

[0044] Further treating a treated catalyst composition of the presentinvention (i.e., a catalyst composition which has been contacted with afirst treating agent as disclosed herein) with a second treating agentaccording to a process of the present invention is generally carried outby contacting such treated catalyst composition with a second treatingagent under a second treating condition as disclosed herein. The treatedcatalyst composition, which can be contained within a treating zone, canbe contacted by any suitable manner with a second treating agent under asecond treating condition as disclosed herein. Such treating zone cancomprise, for example, a reactor vessel.

[0045] A second treating condition of the present invention comprises atemperature of at least about 50° F., preferably at least about 100° F.,and more preferably at least about 200° F. Generally, the secondtreating condition comprises a temperature of no more than about 800°F., preferably no more than about 600° F., and more preferably no morethan about 500° F. The second treating condition also comprises apressure of at least about atmospheric (i.e., about 14.7 pounds persquare inch absolute), and generally no more than about 150 pounds persquare inch absolute (psia), preferably no more than about 100 psia. Thepressure is more preferably about atmospheric. The second treatingcondition also comprises a time period generally of at least about 0.1hour and generally no more than about 50 hours, preferably no more thanabout 40 hours, and more preferably no more than about 30 hours.

[0046] A second treating condition of the present invention furthercomprises the flow rate at which the second treating agent, preferably ahydrogen-containing fluid, is charged (i.e., the charge rate of secondtreating agent) to the treating zone. The flow rate is such as toprovide a gas hourly space velocity (“GHSV”) generally exceeding 1 literof second treating agent per liter of catalyst composition per hour(liter/liter/hour). The term “gas hourly space velocity” has beendescribed herein. Generally, the gas hourly space velocity of the secondtreating agent will be at least about 1 liter/liter/hour, preferably atleast about 500 liter/liter/hour, and more preferably at least about 750liter/liter/hour. Generally, the gas hourly space velocity of the secondtreating agent will be no more than about 50,000 liter/liter/hour,preferably no more than about 40,000 liter/liter/hour, and morepreferably no more than about 30,000 liter/liter/hour.

[0047] Further treating a treated catalyst composition of the presentinvention with a second treating agent under a second treating conditionaccording to a process of the present invention can be operated as abatch process or, preferably, as a continuous process. In the latteroperation, a solid or fixed catalyst bed or a moving catalyst bed or afluidized catalyst bed can be employed. Preferably, a fixed catalyst bedis employed. Any of these operational modes have advantages anddisadvantages, and those skilled in the art can select the one mostsuitable for a particular catalyst composition and second treatingagent.

[0048] In a more preferred treating process of the present invention, acatalyst composition is contacted with a first treating agent(preferably a hydrogen-containing fluid which contains carbon monoxide,more preferably a hydrogen gas stream which contains carbon monoxide)under a first treating condition to provide a treated catalystcomposition. The carbon monoxide being provided to suchhydrogen-containing fluid is then stopped allowing a hydrogen-containingfluid (preferably hydrogen gas) to continue contacting the treatedcatalyst composition under a second treating condition to further treatthe treated catalyst composition.

[0049] According to another embodiment of the present invention, ahydrogenation process is provided. The hydrogenation process of thisinvention can comprise contacting a hydrocarbon-containing fluid whichcomprises one or more highly unsaturated hydrocarbon(s) such as anaromatic hydrocarbon(s), alkyne(s), and/or diolefin(s) with a treatedcatalyst composition of the present invention in the presence ofhydrogen in a hydrogenation zone under a hydrogenation condition tohydrogenate such one or more highly unsaturated hydrocarbon(s) to a lessunsaturated hydrocarbon such as a monoolefin. The highly unsaturatedhydrocarbon(s) is present in the hydrocarbon-containing fluid as animpurity generally at a level found in typical commercial feed streams.Generally, the hydrocarbon-containing fluid comprises at least about 1part by weight highly unsaturated hydrocarbon(s) per billion parts byweight hydrocarbon-containing fluid (i.e., about 1 ppb), typically atleast about 10 ppb, and more typically at least about 100 ppb.Generally, the hydrocarbon-containing fluid comprises no more than about10 weight percent highly unsaturated hydrocarbon, typically no more thanabout 8 weight percent, and more typically no more than about 3 weightpercent.

[0050] Hydrogen can be present either in the hydrocarbon-containingfluid or in a hydrogen-containing fluid which is mixed with thehydrocarbon-containing fluid before contacting with a treated catalystcomposition of the present invention. If a hydrogen-containing fluid isused, it can be a hydrogen gas stream or any fluid containing asufficient concentration of hydrogen to effect the hydrogenationdisclosed herein. It can also contain other gases such as, for example,nitrogen, methane, carbon monoxide, carbon dioxide, steam, orcombinations thereof so long as the hydrogen-containing fluid contains asufficient concentration of hydrogen to effect the hydrogenationdisclosed herein.

[0051] The hydrocarbon-containing fluid of the hydrogenation process(es)of the present invention can also comprise one or more less unsaturatedhydrocarbon(s) such as a monoolefin(s) and one or more saturatedhydrocarbon(s) such as an alkane(s). These additional hydrocarbons canbe present in the hydrocarbon-containing fluid at a level of at leastabout 0.001 weight percent and no more than about 99.999 weight percent.

[0052] Examples of suitable alkynes include, but are not limited to,acetylene, propyne (also referred to as methylacetylene), 1-butyne,2-butyne, 1-pentyne, 2-pentyne, 3-methyl-1-butyne, 1-hexyne, 1-heptyne,1-octyne, 1-nonyne, 1-decyne, and the like and combinations thereof. Thepresently preferred alkynes are acetylene and propyne.

[0053] The alkynes are primarily hydrogenated to the correspondingalkenes. For example, acetylene is primarily hydrogenated to ethylene;propyne is primarily hydrogenated to propylene; and the butynes areprimarily hydrogenated to the corresponding butenes (e.g., 1-butene,2-butenes).

[0054] Examples of suitable diolefins include those generally containingat least about 3 carbon atoms per molecule and generally containing nomore than about 12 carbon atoms per molecule. Such diolefins include,but are not limited to, propadiene, 1,2-butadiene, 1,3-butadiene,isoprene, 1,2-pentadiene, 1,3-pentadiene, 1,4-pentadiene, 1,2-hexadiene,1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2-methyl-1,2-pentadiene,2,3-dimethyl-1,3-butadiene, heptadienes, methylhexadienes, octadienes,methylheptadienes, dimethylhexadienes, ethylhexadienes,trimethylpentadienes, methyloctadienes, dimethylheptadienes,ethyloctadienes, trimethylhexadienes, nonadienes, decadienes,undecadienes, dodecadienes, cyclopentadienes, cyclohexadienes,methylcyclopentadienes, cycloheptadienes, methylcyclohexadienes,dimethylcyclopentadienes, ethylcyclopentadienes, dicyclopentadiene (alsoknown as tricyclo[5.2.1]^(2,6)deca-3,8-diene), and the like andcombinations thereof. Presently preferred diolefins are propadiene,1,2-butadiene, 1,3-butadiene, pentadienes (such as 1,3-pentadiene,1,4-pentadiene, isoprene), cyclopentadienes (such as1,3-cyclopentadiene) and dicyclopentadiene. These diolefins arepreferably hydrogenated to their corresponding monoolefins containingthe same number of carbon atoms per molecule as the diolefins. Forexample, propadiene is hydrogenated to propylene, 1,2-butadiene and1,3-butadiene are hydrogenated to 1-butene and 2-butene, 1,3-pentadieneand 1,4-pentadiene are hydrogenated to 1-pentene and 2-pentene, isopreneis hydrogenated to methyl-1-pentenes and methyl-2-pentenes, and1,3-cyclopentadiene is hydrogenated to cyclopentene.

[0055] Examples of suitable aromatic hydrocarbons include, but are notlimited to, benzene, toluene, ethylbenzene, styrene, xylenes, and thelike and combinations thereof.

[0056] Examples of suitable monoolefins include, but are not limited to,ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene,2-pentene, methyl-1-butenes (such as 2-methyl-1-butene),methyl-2-butenes (such as 2-methyl-2-butene), 1-hexene, 2-hexene,3-hexene, methyl-l-pentenes, 2,3-dimethyl-1-butene, 1-heptene,2-heptene, 3-heptene, methyl-1-hexenes, methyl-2-hexenes,methyl-3-hexenes, dimethylpentenes, ethylpentenes, octenes,methylheptenes, dimethylhexenes, ethylhexenes, nonenes, methyloctenes,dimethylheptenes, ethylheptenes, trimethylhexenes, cyclopentene,cyclohexene, methylcyclopentene, cycloheptene, methylcyclohexene,dimethylcyclopentenes, ethylcyclopentenes, cyclooctenes,methylcycloheptenes, dimethylcyclohexenes, ethylcyclohexenes,trimethylcyclohexenes, methylcyclooctenes, dimethylcyclooctenes,ethylcyclooctenes, and the like and combinations thereof.

[0057] Examples of suitable saturated hydrocarbons include, but are notlimited to, methane, ethane, propane, butane, methylpropane,methylbutane, dimethylbutane, pentanes, hexanes, and the like andcombinations thereof.

[0058] Further, the hydrocarbon-containing fluid can contain up to about5000 parts per million by volume (ppmv) of carbon monoxide.

[0059] The hydrocarbon-containing fluid disclosed herein may contain animpurity. The term “impurity” as used herein denotes any component in ahydrocarbon-containing fluid that is not a major component. Examples ofimpurities other than an alkyne or a diolefin include, but are notlimited to carbon monoxide, hydrogen sulfide, carbonyl sulfide (COS),carbon disulfide (CS₂), mercaptans (RSH), organic sulfides (RSR),organic disulfides (RSSR), thiophene, organic trisulfides, organictetrasulfides, and the like and combinations thereof, wherein each R canbe an alkyl or cycloalkyl or aryl group containing at least about 1carbon atom and generally no more than about 15 carbon atoms, preferablyno more than about 10 carbon atoms. It is within the scope of thisinvention to have additional compounds (such as water, alcohols, ethers,aldehydes, ketones, carboxylic acids, esters, other oxygenatedcompounds, and the like and combinations thereof) present in thehydrocarbon-containing fluid, as long as they do not significantlyinterfere with the hydrogenation process of a highly unsaturatedhydrocarbon to a less unsaturated hydrocarbon as described herein.

[0060] The hydrogenation process(es) of the present invention isgenerally carried out by contacting a hydrocarbon-containing fluidcomprising at least one highly unsaturated hydrocarbon, in the presenceof hydrogen, with a treated catalyst composition of the presentinvention under a hydrogenation condition. The hydrocarbon-containingfluid can be contacted by any suitable manner with the treated catalystcomposition which is contained within a hydrogenation zone. Suchhydrogenation zone can comprise, for example, a reactor vessel. Thetreating zone and hydrogenation zone of the present invention can be thesame zone or different zones. For example, a treating process of thepresent invention can be conducted in a treating zone comprising areactor vessel. After completing the treatment process described herein,a hydrogenation process of the present invention can then be conductedin the same reactor vessel.

[0061] The contacting step, of contacting a hydrocarbon-containing fluidwith a treated catalyst composition of the present invention, can beoperated as a batch process step or, preferably, as a continuous processstep. In the latter operation, a solid or fixed catalyst bed or a movingcatalyst bed or a fluidized catalyst bed can be employed. Preferably, afixed catalyst bed is employed. Any of these operational modes haveadvantages and disadvantages, and those skilled in the art can selectthe one most suitable for a particular hydrocarbon-containing fluid andtreated catalyst composition.

[0062] The contacting step is preferably carried out within ahydrogenation zone, wherein is contained a treated catalyst compositionof the present invention, and under a hydrogenation condition thatsuitably promotes the hydrogenation process of a highly unsaturatedhydrocarbon to a less unsaturated hydrocarbon. Such hydrogenationcondition should be such as to avoid significant hydrogenation of a lessunsaturated hydrocarbon(s) being initially present in thehydrocarbon-containing fluid to a saturated hydrocarbon(s) such as analkane(s) or cycloalkane(s).

[0063] Generally, such hydrogenation process comprises the presence ofhydrogen, preferably hydrogen gas, in an amount of at least about 0.1mole of hydrogen employed for each mole of highly unsaturatedhydrocarbon present in the hydrocarbon-containing fluid, preferably atleast about 0.5 mole of hydrogen, and more preferably at least about 0.7mole of hydrogen. Generally, such hydrogenation process comprises nomore than about 1000 moles of hydrogen employed for each mole of highlyunsaturated hydrocarbon present in the hydrocarbon-containing fluid,preferably no more than about 500 moles of hydrogen, and more preferablyno more than about 200 moles of hydrogen.

[0064] Generally, such hydrogenation condition comprises a temperatureand a pressure necessary for the hydrogenation process(es) of thepresent invention depending largely upon the activity of the treatedcatalyst composition, the hydrocarbon-containing fluid, and the desiredextent of hydrogenation. Generally, such temperature is at least about50° F., preferably at least about 60° F., and more preferably at leastabout 70° F. Generally, such temperature is no more than about 600° F.,preferably no more than about 500° F., and more preferably no more thanabout 400° F. A suitable pressure is generally at least about 15 poundsper square inch gauge (psig), preferably at least about 50 psig, andmore preferably at least about 100 psig. Generally, a suitable pressureis no more than about 2000 psig, preferably no more than about 1500psig, and more preferably no more than about 1000 psig.

[0065] Such hydrogenation condition further comprises the flow rate atwhich the hydrocarbon-containing fluid is charged (i.e., the charge rateof hydrocarbon-containing fluid) to the hydrogenation zone. The flowrate is such as to provide a gas hourly space velocity (“GHSV”)generally exceeding 1 liter of hydrocarbon-containing fluid per liter oftreated catalyst composition per hour (liter/liter/hour). The term “gashourly space velocity” has been described herein. Typically, the gashourly space velocity of the hydrocarbon-containing fluid will be atleast about 1 liter/liter/hour, preferably at least about 750liter/liter/hour, and more preferably at least about 1000liter/liter/hour. Typically, the gas hourly space velocity will be nomore than about 50,000 liter/liter/hour, preferably no more than about40,000 liter/liter/hour, and more preferably no more than about 30,000liter/liter/hour.

[0066] If it is desired to regenerate a treated catalyst composition ofthe present invention after prolonged use in a hydrogenation process(es)described herein, the regeneration can be accomplished by calcining thetreated catalyst composition in an oxidizing atmosphere such as in airat a temperature that does not exceed about 1300° F. to burn offcarbonaceous and sulfur deposits. Optionally, the catalyst compositioncan be reimpregnated with palladium and a catalyst component comprisingeither silver or an alkali metal compound, or both silver and an alkalimetal compound, and then dried and calcined for the production of afresh catalyst composition which can then be subjected to a treatingprocess of the present invention to provide a treated catalystcomposition.

[0067] The following examples are presented to further illustrate thepresent invention and are not to be construed as unduly limiting thescope of the present invention.

EXAMPLE I

[0068] This example describes the untreated catalyst composition,catalyst composition treating process, and reaction process utilized inExamples II through V unless otherwise noted in such Examples.

[0069] Catalyst A was a commercially-available material designated“G58D” obtained from United Catalysts Inc., Louisville, Ky. Catalyst Acontained 0.016 to 0.018 weight percent palladium and 0.11 weightpercent silver on aluminum oxide support.

[0070] The catalyst treating process was conducted as follows. About 20cc (23 grams) of the above-described Catalyst A were mixed with 40 mL ofalundum (an inert material) and placed in a stainless steel jacketedreactor tube having a 0.75 inch inner diameter and a length of about 18inches. The catalyst resided in the middle of the reactor and both endsof the reactor were packed with about 10 cc of alundum. The reactiontemperature was controlled by circulating ethylene glycol through thejacket of the reactor tube. The catalyst was then treated by contactingthe catalyst with a first treating agent by passing such first treatingagent over the catalyst at 200 milliliters per minute (mL/min) atatmospheric pressure at 395° F. for two hours to provide a treatedcatalyst. In some of the Examples, the treated catalyst was thencontacted with a second treating agent by passing such second treatingagent over the treated catalyst at 200 mL/min at atmospheric pressure at395° F. for two hours.

[0071] The reaction process was then conducted as follows. A feed gas(approximately: 15 wt % methane, 83 wt % ethylene, 1.1 wt % acetylene,and 0.1 wt % hydrogen (1.3 hydrogen to acetylene molar ratio)) wascontacted with the catalyst by passing the feed gas over the catalyst atabout 913 cc/min at 200 pounds per square inch gauge (psig). Thereaction temperature was varied to yield a specific conversion ofacetylene. Conversion of acetylene is defined as the percent ofacetylene that was consumed from the feed gas. The temperature was thenheld constant for 24 to 48 hours with the feed continually contacting,i.e., passing over, the catalyst. Samples of the product were analyzedat various time intervals by means of a gas chromatograph. After about20 to 40 hours, the reactor temperature was varied to achieve aconversion of acetylene between 80% and 100%. Selectivities werecalculated on a weight basis from the gas chromatography data.

EXAMPLE II

[0072] This example demonstrates the effect of using carbon monoxide asthe first treating agent. All runs utilized Catalyst A, the catalysttreating process, and the reaction process as described herein inExample I, except a second treating agent was not used. Control Run 2Autilized hydrogen gas as the first treating agent. Invention Run 2Butilized 5 mole percent carbon monoxide in hydrogen gas as the firsttreating agent. Invention Run 2C utilized 5 mole percent carbon monoxidein nitrogen gas as the first treating agent. The results of Example IIare shown in Table I. TABLE I FIRST 80% CONVERSION 90% CONVERSIONMAXIMUM CONVERSION ACTIVATING TEMP. SELECTIVITY TEMP. SELECTIVITY TEMP.SELECTIVITY RUN TYPE AGENT (° F.) TO ETHYLENE (° F.) TO ETHYLENECONVERSION (° F.) TO ETHYLENE 2A Control H₂ 117 64 123 60 99.6 146 16 2BInvention 5% CO/H₂ 99 59 105 55 99.4 120 20 2C Invention 5% CO/N₂ 89 5897 43 98.4 150 29

[0073] The data in Table I clearly demonstrate that a first treatingagent comprising carbon monoxide significantly lowered the reactiontemperature for a given conversion.

EXAMPLE III

[0074] This example demonstrates the effect of utilizing a firsttreating agent comprising carbon monoxide followed by utilizing a secondtreating agent comprising hydrogen gas. All runs utilized Catalyst A,the catalyst treating process, and the reaction process as describedherein in Example I. Control Run 3A utilized hydrogen gas as the firsttreating agent without utilizing a second treating agent. Control Run 3Butilized hydrogen gas as both the first and second treating agent.Invention Run 3C utilized 5 mole percent carbon monoxide in hydrogen gasas the first treating agent and hydrogen gas as the second treatingagent. Invention Run 3D utilized 5 mole percent carbon monoxide innitrogen gas as the first treating agent and hydrogen gas as the secondtreating agent. The results of Example III are shown in Table II. TABLEII FIRST SECOND ACTIVAT- ACTIVAT- 80% CONVERSION 90% CONVERSION MAXIMUMCONVERSION ING ING TEMP. SELECTIVITY TEMP. SELECTIVITY CONVER- TEMP.SELECTIVITY RUN TYPE AGENT AGENT (° F.) TO ETHYLENE (° F.) TO ETHYLENESION (° F.) TO ETHYLENE 3A Control H₂ — 117 64 123 60 99.6 146 16 3BControl H₂ H₂ 134 64 139 54 99.5 195 −4 3C Invention 5% CO/H₂ H₂ 101 66108 61 99.2 156 18 3D Invention 5% CO/N₂ H₂ — — 107 56 99.6 172 15

[0075] The data in Table II clearly demonstrate that the catalyst isless active (the reaction temperature increases) and selectivity athigher conversions is less when the catalyst is contacted for a longerperiod of time with a treating agent of hydrogen gas (compare Runs 3Aand 3B). The data in Table II also clearly demonstrate that utilizing afirst treating agent of 5 mole percent carbon monoxide in hydrogen gasfollowed by contacting with a second treating agent of hydrogen gas(Invention Run 3C) provides a more active catalyst (lower reactiontemperature) at lower conversions with relatively similar selectivity atall conversions (compare Invention Run 3C to Control Runs 3A and 3B).The data in Table II also clearly demonstrate that utilizing a firsttreating agent of 5 mole percent carbon monoxide in nitrogen gasfollowed by contacting with a second treating agent of hydrogen gas(Invention Run 3D) provides a significantly more active (lower reactiontemperature) and selective catalyst at 90% conversion (compare InventionRun 3D to Control Runs 3A and 3B).

EXAMPLE IV

[0076] This example demonstrates the effect of using a first treatingagent comprising carbon monoxide, both in situ and ex situ, andoptionally using a second treating agent of hydrogen gas in situ. Allruns utilized Catalyst A, the catalyst treating process, and thereaction process as described herein in Example I with the exceptionsregarding in situ and ex situ. Control Run 4A utilized hydrogen gas, insitu, as the first treating agent without utilizing a second treatingagent. Control Run 4B utilized hydrogen gas, in situ, as both the firstand second treating agent. Control Run 4C utilized 5 mole percent carbonmonoxide in nitrogen gas as the first treating agent followed bycontacting with a second treating agent of hydrogen gas, all in situ(i.e., the catalyst was never exposed to air between contacting with thefirst and second treating agents). Control Run 4D was conducted in thesame manner as Control Run 4C except that contacting with a secondtreating agent was not conducted. Invention Run 4E utilized 5 molepercent carbon monoxide in nitrogen gas as the first treating agent exsitu (i.e., contacting with the first treating agent was conductedoutside the stainless steel jacketed reactor tube in a separateglass-tube reactor under the conditions as described herein in ExampleI) followed by cooling to room temperature, exposing to air, loading thecatalyst into the stainless steel jacketed reactor tube followed bycontacting with a second treating agent of hydrogen gas in situ.Invention Run 4F was conducted in the same manner as Invention Run 4Ewith the exception that, once the catalyst was loaded into the stainlesssteel jacketed reactor tube, the reactor was pressurized anddepressurized three times with hydrogen gas to 200 pounds per squareinch gauge (psig) to help remove any traces of air instead of contactingwith a second treating agent. The results of Example IV are shown inTable III. TABLE III FIRST SECOND ACTIVAT- ACTIVAT- 80% CONVERSION 90%CONVERSION MAXIMUM CONVERSION ING ING TEMP. SELECTIVITY TEMP.SELECTIVITY CONVER- TEMP. SELECTIVITY RUN TYPE AGENT AGENT (° F.) TOETHYLENE (° F.) TO ETHYLENE SION (° F.) TO ETHYLENE 4A Control H₂* — 11764 123 60 99.6 146 16 4B Control H₂* H₂* 134 64 139 54 99.5 195 −4 4CInvention 5% CO/N₂* H₂* — — 107 56 99.6 172 15 4D Invention 5% CO/N₂* — 89 58  97 43 98.4 150 29 4E Invention 5% CO/N₂** H₂* 118 62 — — 99.7146 27 4F Invention 5% CO/N₂** — 116 66 122 52 — — —

[0077] The data in Table III clearly demonstrate that utilizing 5 molepercent carbon monoxide in nitrogen, either in situ or ex situ, yields amore active catalyst at lower conversions and a more selective catalystat higher conversions compared to the control (compare Invention Runs 4Dand 4F to Control Run 4A). The data in Table III also demonstrate thatutilizing 5 mole percent carbon monoxide in nitrogen, either in situ orex situ, followed by a second hydrogen treatment yields a catalyst thatis more active than the control as well as more selective at higherconversions than the control (compare Invention Runs 4C and 4E toControl Run 4B).

EXAMPLE V

[0078] This example demonstrates the effect of the carbon monoxideconcentration in the first treating agent comprising such carbonmonoxide and hydrogen gas. A second treating agent was not utilized. Allruns utilized Catalyst A, the catalyst treating process, and thereaction process as described herein in Example I. The results ofExample V are shown in Table IV. TABLE IV % CO in H₂ OF FIRST 80%CONVERSION 90% CONVERSION MAXIMUM CONVERSION ACTIVATING TEMP.SELECTIVITY TEMP. SELECTIVITY TEMP. SELECTIVITY RUN TYPE AGENT (° F.) TOETHYLENE (° F.) TO ETHYLENE CONVERSION (° F.) TO ETHYLENE 5A Control 0117 64 123 60 99.6 146 16 5B Invention 0.05 70 67 74 50 99.4 87 −7 5CInvention 0.1 70 67 74 56 99.5 85 3 5D Invention 0.5 75 68 79 60 99.6 939 5E Invention 5 99 59 105 55 99.4 120 20

[0079] The data in Table IV clearly demonstrate that adding carbonmonoxide in the first treating agent comprising such carbon monoxide andhydrogen gas significantly increases the catalyst's activity. The datain Table IV demonstrate that the catalyst activity is inverselyproportional to the concentration of carbon monoxide in the firsttreating agent comprising such carbon monoxide and hydrogen gas. Thedata in Table IV also demonstrate that no significant change inselectivity was observed at the 80% and 90% conversions. However, athigh conversion the selectivity decreased when the concentration ofcarbon monoxide was below approximately 0.5%.

[0080] The results shown in the above examples clearly demonstrate thatthe present invention is well adapted to carry out the objects andattain the ends and advantages mentioned as well as those inherenttherein.

[0081] Reasonable variations, modifications, and adaptations can be madewithin the scope of the disclosure and the appended claims withoutdeparting from the scope of this invention.

What is claimed is:
 1. A process of treating a catalyst compositioncomprising contacting a catalyst composition with a first treating agentcomprising carbon monoxide under a first treating condition to provide atreated catalyst composition.
 2. A process according to claim 1 whereinsaid first treating agent further comprises an additional componentselected from the group consisting of a hydrogen-containing fluid, aninert gas, a hydrocarbon-containing gas, and combinations thereof.
 3. Aprocess according to claim 2 wherein said hydrogen-containing fluid ishydrogen gas.
 4. A process according to claim 2 wherein said inert gasis selected from the group consisting of nitrogen, argon, andcombinations thereof.
 5. A process according to claim 1 wherein saidfirst treating agent comprises a mole percentage of said carbon monoxideof at least about 0.0005 and said first treating agent comprises a molepercentage of said carbon monoxide of no more than about
 50. 6. Aprocess according to claim 1 wherein said first treating conditioncomprises: a temperature wherein said temperature is at least about 50°F. and further wherein said temperature is no more than about 800° F., apressure wherein said pressure is at least about atmospheric and furtherwherein said pressure is no more than about 150 psia, a time periodwherein said time period is at least about 0.1 hour and further whereinsaid time period is no more than about 50 hours, and a gas hourly spacevelocity wherein said gas hourly space velocity is at least about 1liter of said first treating agent per liter of said catalystcomposition per hour (liter/liter/hour) and further wherein said gashourly space velocity is no more than about 50,000 liter/liter/hour. 7.A process according to claim 1 wherein said catalyst compositioncomprises at least about 0.0001 weight percent palladium based on thetotal weight of said catalyst composition and further wherein saidcatalyst composition comprises no more than about 3 weight percentpalladium.
 8. A process according to claim 1 wherein said catalystcomposition further comprises a catalyst component selected from thegroup consisting of silver, modifiers, and combinations thereof.
 9. Aprocess according to claim 8 wherein said modifiers comprise an alkalimetal compound.
 10. A process according to claim 9 wherein said alkalimetal compound is an alkali metal iodide or an alkali metal fluoride.11. A process according to claim 7 wherein said catalyst compositioncomprises at least about 0.0003 weight percent silver based on the totalweight of said catalyst composition and further wherein said catalystcomposition comprises no more than about 20 weight percent silver.
 12. Aprocess according to claim 11 wherein said catalyst composition furthercomprises an alkali metal fluoride and further wherein said catalystcomposition comprises at least about 0.02 weight percent fluorinechemically bound as fluoride on a total catalyst composition weightbasis and further wherein said catalyst composition comprises no morethan about 10 weight percent fluorine.
 13. A process according to claim7 wherein said catalyst composition further comprises an inorganicsupport selected from the group consisting of alumina, aluminates,titania, zirconia, and combinations thereof.
 14. A process according toclaim 2 wherein said inert gas is nitrogen.
 15. A process according toclaim 2 wherein said hydrocarbon-containing gas is methane.
 16. Aprocess according to claim 1 wherein said first treating agent comprisescarbon monoxide and a hydrogen-containing fluid.
 17. A process accordingto claim 1 wherein said first treating agent comprises carbon monoxideand nitrogen.
 18. A process according to claim 1 wherein said firsttreating agent comprises carbon monoxide in the form of formic acidvapor diluted in an inert gas.
 19. A process according to claim 1wherein said process further comprises contacting said treated catalystcomposition with a second treating agent comprising ahydrogen-containing fluid under a second treating condition.
 20. Aprocess according to claim 19 wherein said second treating agent furthercomprises an additional component selected from the group consisting ofcarbon monoxide, an inert gas, a hydrocarbon-containing gas, andcombinations thereof.
 21. A process according to claim 19 wherein saidhydrogen-containing fluid is hydrogen gas.
 22. A process according toclaim 20 wherein said inert gas is selected from the group consisting ofnitrogen, argon, and combinations thereof.
 23. A process according toclaim 20 wherein said hydrocarbon-containing gas is methane.
 24. Aprocess according to claim 19 wherein said second treating conditioncomprises: a temperature wherein said temperature is at least about 50°F. and further wherein said temperature is no more than about 800° F., apressure wherein said pressure is at least about atmospheric and furtherwherein said pressure is no more than about 150 psia, a time periodwherein said time period is at least about 0.1 hour and further whereinsaid time period is no more than about 50 hours, and a gas hourly spacevelocity wherein said gas hourly space velocity is at least about 1liter of said second treating agent per liter of said catalystcomposition per hour (liter/liter/hour) and further wherein said gashourly space velocity is no more than about 50,000 liter/liter/hour. 25.A process according to claim 19 wherein said treated catalystcomposition is not exposed to air before said treated catalystcomposition is contacted with said second treating agent.
 26. A processaccording to claim 19 wherein said treated catalyst composition isexposed to air before said treated catalyst composition is contactedwith said second treating agent.
 27. A composition prepared by theprocess of claim
 1. 28. A composition prepared by the process of claim2.
 29. A composition prepared by the process of claim
 6. 30. Acomposition prepared by the process of claim
 7. 31. A compositionprepared by the process of claim
 8. 32. A composition prepared by theprocess of claim
 14. 33. A composition prepared by the process of claim19.
 34. A composition prepared by the process of claim
 20. 35. Acomposition prepared by the process of claim
 24. 36. A compositionprepared by the process of claim 25
 37. A process comprising contactinga hydrocarbon-containing fluid which comprises a highly unsaturatedhydrocarbon with a treated catalyst composition in the presence ofhydrogen in a hydrogenation zone under a hydrogenation conditioneffective to hydrogenate said highly unsaturated hydrocarbon to a lessunsaturated hydrocarbon wherein said treated catalyst composition isprepared by the process of claim
 1. 38. A process comprising contactinga hydrocarbon-containing fluid which comprises a highly unsaturatedhydrocarbon with a treated catalyst composition in the presence ofhydrogen in a hydrogenation zone under a hydrogenation conditioneffective to hydrogenate said highly unsaturated hydrocarbon to a lessunsaturated hydrocarbon wherein said treated catalyst composition isprepared by the process of claim
 2. 39. A process comprising contactinga hydrocarbon-containing fluid which comprises a highly unsaturatedhydrocarbon with a treated catalyst composition in the presence ofhydrogen in a hydrogenation zone under a hydrogenation conditioneffective to hydrogenate said highly unsaturated hydrocarbon to a lessunsaturated hydrocarbon wherein said treated catalyst composition isprepared by the process of claim
 6. 40. A process comprising contactinga hydrocarbon-containing fluid which comprises a highly unsaturatedhydrocarbon with a treated catalyst composition in the presence ofhydrogen in a hydrogenation zone under a hydrogenation conditioneffective to hydrogenate said highly unsaturated hydrocarbon to a lessunsaturated hydrocarbon wherein said treated catalyst composition isprepared by the process of claim
 14. 41. A process comprising contactinga hydrocarbon-containing fluid which comprises a highly unsaturatedhydrocarbon with a treated catalyst composition in the presence ofhydrogen in a hydrogenation zone under a hydrogenation conditioneffective to hydrogenate said highly unsaturated hydrocarbon to a lessunsaturated hydrocarbon wherein said treated catalyst composition isprepared by the process of claim
 19. 42. A process comprising contactinga hydrocarbon-containing fluid which comprises a highly unsaturatedhydrocarbon with a treated catalyst composition in the presence ofhydrogen in a hydrogenation zone under a hydrogenation conditioneffective to hydrogenate said highly unsaturated hydrocarbon to a lessunsaturated hydrocarbon wherein said treated catalyst composition isprepared by the process of claim
 20. 43. A process according to claim 37wherein said highly unsaturated hydrocarbon is selected from the groupconsisting of alkynes, diolefins, and combinations thereof.
 44. Aprocess according to claim 43 wherein said alkynes are selected from thegroup consisting of acetylene, propyne, 1-butyne, 2-butyne, 1-pentyne,2-pentyne, 3-methyl-1-butyne, 1-hexyne, 1-heptyne, 1-octyne, 1-nonyne,1-decyne, and combinations thereof.
 45. A process according to claim 44wherein said alkynes are acetylene and propyne.
 46. A process accordingto claim 45 wherein said diolefins contain at least about 3 carbon atomsper molecule and no more than about 12 carbon atoms per molecule.
 47. Aprocess according to claim 46 wherein said diolefins are selected fromthe group consisting of propadiene, 1,2-butadiene, 1,3-butadiene,isoprene, 1,2-pentadiene, 1,3-pentadiene, 1,4-pentadiene, 1,2-hexadiene,1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2-methyl-1,2-pentadiene,2,3-dimethyl-1,3-butadiene, heptadienes, methylhexadienes, octadienes,methylheptadienes, dimethylhexadienes, ethylhexadienes,trimethylpentadienes, methyloctadienes, dimethylheptadienes,ethyloctadienes, trimethylhexadienes, nonadienes, decadienes,undecadienes, dodecadienes, cyclopentadienes, cyclohexadienes,methylcyclopentadienes, cycloheptadienes, methylcyclohexadienes,dimethylcyclopentadienes, ethylcyclopentadienes, dicyclopentadiene, andcombinations thereof.
 48. A process according to claim 47 wherein saiddiolefins are selected from the group consisting of propadiene,1,2-butadiene, 1,3-butadiene, pentadienes, cyclopentadienes,dicyclopentadiene, and combinations thereof.
 49. A process according toclaim 48 wherein said less unsaturated hydrocarbon is selected from thegroup consisting of ethylene, propylene, 1-butene, 2-butene,isobutylene, 1-pentene, 2-pentene, methyl-1-butenes, methyl-2-butenes,1-hexene, 2-hexene, 3-hexene, methyl-1-pentenes, 2,3-dimethyl-1-butene,1-heptene, 2-heptene, 3-heptene, methyl-1-hexenes, methyl-2-hexenes,methyl-3-hexenes, dimethylpentenes, ethylpentenes, octenes,methylheptenes, dimethylhexenes, ethylhexenes, nonenes, methyloctenes,dimethylheptenes, ethylheptenes, trimethylhexenes, cyclopentene,cyclohexene, methylcyclopentene, cycloheptene, methylcyclohexene,dimethylcyclopentenes, ethylcyclopentenes, cyclooctenes,methylcycloheptenes, dimethylcyclohexenes, ethylcyclohexenes,trimethylcyclohexenes, methylcyclooctenes, dimethylcyclooctenes,ethylcyclooctenes, and combinations thereof.
 50. A process according toclaim 49 wherein said hydrocarbon-containing fluid further comprises amonoolefin.
 51. A process according to claim 50 wherein said monoolefinis selected from the group consisting of ethylene, propylene, 1-butene,2-butene, isobutylene, 1-pentene, 2-pentene, methyl-1-butenes,methyl-2-butenes, 1-hexene, 2-hexene, 3-hexene, methyl-1-pentenes,2,3-dimethyl-1-butene, 1-heptene, 2-heptene, 3-heptene,methyl-1-hexenes, methyl-2-hexenes, methyl-3-hexenes, dimethylpentenes,ethylpentenes, octenes, methylheptenes, dimethylhexenes, ethylhexenes,nonenes, methyloctenes, dimethylheptenes, ethylheptenes,trimethylhexenes, cyclopentene, cyclohexene, methylcyclopentene,cycloheptene, methylcyclohexene, dimethylcyclopentenes,ethylcyclopentenes, cyclooctenes, methylcycloheptenes,dimethylcyclohexenes, ethylcyclohexenes, trimethylcyclohexenes,methylcyclooctenes, dimethylcyclooctenes, ethylcyclooctenes, andcombinations thereof.
 52. A process according to claim 51 wherein saidhydrocarbon-containing fluid further comprises a saturated hydrocarbonselected from the group consisting of methane, ethane, propane, butane,methylpropane, methylbutane, dimethylbutane, pentanes, hexanes, andcombinations thereof.
 53. A process according to claim 52 wherein saidhydrocarbon-containing fluid further comprises an aromatic hydrocarbonselected from the group consisting of benzene, toluene, ethylbenzene,styrene, xylenes, and combinations thereof.
 54. A process according toclaim 53 wherein said hydrogen is present in an amount of at least about0.1 mole of hydrogen for each mole of said highly unsaturatedhydrocarbon present in said hydrocarbon-containing fluid and furtherwherein said hydrocarbon-containing fluid comprises no more than about1000 moles of hydrogen for each mole of said highly unsaturatedhydrocarbon.
 55. A process according to claim 54 wherein saidhydrogenation condition comprises: a temperature wherein saidtemperature is at least about 50° F. and further wherein saidtemperature is no more than about 600° F., a pressure wherein saidpressure is at least about 15 psig and further wherein said pressure isno more than about 2000 psig, and a charge rate of saidhydrocarbon-containing fluid to said hydrogenation zone such as toprovide a gas hourly space velocity of at least about 1 liter of saidhydrocarbon-containing fluid per liter of said treated catalystcomposition per hour (liter/liter/hour) and further wherein said gashourly space velocity is no more than about 50,000 liter/liter/hour.